#include<stdio.h>

void change1(int* a, int* b)
{
	*a = *a + *b;
	*b = *a - *b;
	*a = *a - *b;
}
void change2(int* a, int* b)
{
	*a = *a ^ *b;
	*b = *a ^ *b;
	*a = *a ^ *b;

}
void change3(int* a, int* b)
{
	int tem = 0;
	tem = *a;
	*a = *b;
	*b = tem;
}
int main()
{
	int a = 10;
	int b = 20;
	change1(&a, &b);
	printf("%d,%d\n", a, b);

	change2(&a, &b);
	printf("%d,%d\n", a, b);

	change3(&a, &b);
	printf("%d,%d\n", a, b);


	return 0;
}